More than 1,000 people took to the streets of San Francisco last night with a single, unmistakable message for a visiting President Obama: Reject the Keystone XL pipeline. The Center for Biological Diversity joined other environmental groups in organizing this amazing protest, and we want to thank all our supporters who participated.

The rally included a brass band, hundreds of signs and an entertaining appearance by the Center's very own Frostpaw the Polar Bear. With Obama in town for a fundraiser, we made it our mission to make sure he heard us loud and clear about the terrible risks Keystone XL poses -- to the climate, wildlife, the environment and, ultimately, the health of us all.

As if we needed any more evidence of the kind of havoc that Keystone XL could deliver, a pipeline carrying tar-sands oil ruptured on Friday in a small Arkansas town, spilling 400,000 gallons of crude in a subdivision and forcing people to evacuate 22 homes.

It's a nasty truth about oil pipelines: Systems fail -- and people and wildlife pay the price. If the Keystone XL pipeline is built, it will transport as many as 35 million gallons of oil a day through a 1,700-mile pipeline from Canada to Texas, cutting across waterways and wildlife habitat for more than 20 imperiled species, including white whooping cranes and the massive, prehistoric pallid sturgeon.

The U.S. State Department says Keystone XL could spill as many as 100 times during the course of its life. We just can't take that risk. The Center for Biological Diversity is joining with people across the United States and beyond in opposing Keystone.

Marbled murrelets -- threatened seabirds that nest in coastal old-growth forests in the Pacific Northwest -- kept their protections this week after a Washington, D.C., district court ruled not to eliminate their federally protected "critical habitat" and remove Endangered Species Act protections they've had since 1992.

The judge ruled in a lawsuit spurred by a proposal by the timber industry to remove protections -- the industry's third try in the past decade to toss out murrelet protections so that it can increase logging of forests more than 100 years old. This is despite undisputed scientific evidence that murrelets are disappearing from the coasts of Washington, Oregon and California. The Center for Biological Diversity has been fighting to protect murrelets since 2005, and we were one of several environmental groups defending the murrelets in the latest timber industry case.

The U.S. Fish and Wildlife Service is pushing a troubling proposal in Florida. The agency is attempting to give the Florida Fish and Wildlife Conservation Commission -- which has a history of ignoring wildlife's wellbeing and close ties to industry influence -- the sole power to OK activities that could harm threatened and endangered species. This would leave the proverbial fox to guard a henhouse full of magnificent species like the Florida panther, Key deer and Cape Sable seaside sparrow from development, mines, pollution and other human-caused dangers.

The Center for Biological Diversity and Conservancy of Southwest Florida have filed a notice of intent to sue the Fish and Wildlife Service for trying to transfer management of those species.

"The Service's move would leave the fate of Florida's most at-risk wildlife in the hands of state leadership that's denying the realities of sea-level rise, whose top priority is eliminating regulations necessary for protecting the environment," said Center attorney and Florida native Jacki Lopez. "Given the scale of development pressure in Florida, federal involvement is essential to ensuring science is followed and species are protected."

The Endangered Species Act turns 40 this year, and we want to make sure the world knows what a success it's been. All year we're teaming up with the Endangered Species Coalition and other environmental groups on a campaign called "A Wild Success: Celebrating 40 Years of the Endangered Species Act."

Will you help us? Throughout the year we're asking people around the country to write letters to the editors of their local newspapers about the power and necessity of the Act. You can write about your favorite species the Act has saved (perhaps the Utah prairie dog or the California condor?), urge Congress not to weaken this bedrock law, or just submit a few lines saying you're thankful for the species' lives the Act saves every day.

This month we're asking people in the Southwest -- Arizona, New Mexico, Utah and Nevada -- to write letters. So if you live in those states, find out how you can help. If you live in another part of the country, fear not but stay tuned -- your time to act for the Act will also come.

After almost 50 years as a climate scientist at NASA's Goddard Institute for Space Studies in New York, Dr. James Hansen -- easily the U.S. government's most visible scientific figure on climate change -- retires this week. Besides being a leading voice urging action on climate change, Hansen, 72, has been arrested or cited at climate protests six times.

Hansen says he intends to be more active in lawsuits against the government over its failure to limit greenhouse gas emissions; he also plans to advocate against the development of dirty tar-sands oil in Canada.

"Dr. Hansen has been an extraordinary, singular force in the scientific and governmental community for swift, ambitious action against climate change," said the Center for Biological Diversity's Climate Law Institute Director Kassie Siegel. "We'll be excited to see him making an impact as a private citizen."

West Hollywood, Calif., is the latest city calling on President Obama to take action on climate change. On Monday, its city council passed a resolution urging the president and the EPA to use the Clean Air Act fully and swiftly to reduce carbon in our atmosphere to no more than 350 parts per million, the level scientists say we must reach to avoid climate catastrophe.

West Hollywood is the 52nd community to join the Center for Biological Diversity's Clean Air Cities campaign. Other cities include Los Angeles, Washington, Miami and Detroit.

"Climate change and extreme weather is a real concern for cities like ours," said West Hollywood Mayor Pro Tempore Abbe Land. "West Hollywood is proud to join cities across America in urging President Obama to wield the Clean Air Act against catastrophic climate change."

Next time your crazy uncle comes back from his seaside vacation ranting about being tracked by a six-foot jellyfish with a camera for an eye and a bundle of wires and electrodes wrapped under its bell, don't be so quick to chalk it up to sunbaked paranoia.

A partnership between the U.S. Navy and Virginia Tech College of Engineering has, in fact, developed such a creature: a military robot jellyfish drone. So far only a prototype, this sci-fi replica of one of the earth's oldest brainless animals has its own 600-gallon swimming pool. The Navy hopes that one day, a fleet of these cyber-gelatinoids will help keep Americans safe -- at least until the enemies of freedom dispatch their own legions of pygmy seahorse attack drones.

Read more at Geek.com and check out this video of brave (and slightly frightened) engineers treading water alongside their monster jelly-droid.